1. Field of the Invention
This invention is related to a suitcase pivoting arm and, more particularly to a pivoting arm for a suitcase to let the suitcase be lifted and positioned at a predetermined angle. When the cover of the suitcase is continuously expanded over the predetermined angle, the pivoting arm will drive the cover of the suitcase to close.
2. Description of Related Art
Conventional suitcases, as shown in FIG. 3, include a casing 1 and a cover 2. In order to support the cover 2 after lifting the suitcase, a pivoting arm is provided to connect the cover 2 with the casing 1. The pivoting arm used in conventional suitcases is substantially comprised of an upper arm member 3 and a lower arm member 4 pivotally connected by an axle pin 5. There are provided concave and convex portions 501 and 502 between the upper and the lower arm members 3 and 4 to provide frictional resistance while the upper and lower arm members 3 and 4 are pivoting against each other, so as to support the cover 2 and prevent the cover from dropping for easily picking up documents or articles from the casing 1 after it is lifted to a certain level.
In the above-described conventional art, the cover is supported by the frictional resistance between the upper and lower arm members. After a certain period of applied resistance, the frictional resistance will be reduced due to wear and tear of the opposing surfaces of the upper and lower arm members, and therefore, the supporting force of the arm members will deteriorate and become insufficient to support the cover. This problem is commonly encountered by suitcase users.
Because the frictional resistance between the upper and lower arm members is constantly provided during a pivoting motion, excessive effort is required to overcome the constant frictional resistance when opening or closing the suitcase. Further, the cover 1 and the casing 2 normally include an inner lining made of plywood. When opening or closing the cover 2, in order to overcome the frictional resistance of the pivoting arm, connecting portions of the two ends 7, 8 of the pivoting arm with the cover, and the casing shall have to bear relative forces applied thereto. Therefore, the pivotally connecting portions of the cover and the casing with the pivoting arm are easy to damage or tear.
Because the cover is supported by the pivoting arm by resistance due to friction if additional or heavy articles are placed in the inner compartment of the cover, the weight of which surpasses the frictional resistance, the pivoting arm will fail to support the cover. It may be suggested to increase the setting value of the frictional resistance for the pivoting arm. However, if the setting value of the frictional resistance for the pivoting arm is excessively high, the connecting portions of the pivoting arm with the cover and the casing are more easily damaged and an increased force must be applied to close or open the suitcase.